advantages and disadvantages of ditching the alternator.

[dbmx66]

what the title says.

id like to get some feed back from you guys.

thanks.

btw theres now specific reason to ditching it, just something ive wondered about

[Super73]

So you are looking at loosing it due to the rotational losses?

Coming from a somewhat electrical background (I have worked in the semiconductor industyr for 12+ years helping engineers design circuits / have learned a lot over the years), you have to think about how a batterey discharges and the current (power) it can put out (sorry Marv, I know this is going to go bad for you ).

Batteries typically don't fair well with high amounts of current being pulled from them. In other words, their life cycle is diminished rather quickly when pulling lots of power from them quickly, and on a regular basis. Batterey make-up (li-ion vs. ni has differences) does play a role in memories of that batterey. Li-ion doesn't have the memory issue a ni batterey does.

A lot of engineers use a capacitor to help off set this issue. A good cap can charge/discharge quickly and help take that strain off the batterey. You see this done a lot in high end car audio as subs require a lot of current. But good caps don't come cheap.

With out going in to a high detail of things, you will potentially kill batteries regularly with out having the alternator to hold a the charge for the required power. How much power do you really use though? During the day, with just the motor running, maybe not much, race at night and a lot more.

I am seeing some companies actually make wireless power tools right now with no batterey, but using a cap to store the energy. This idea could be hold true in a race car too. Charge the large cap between rounds and not worry about it.

You need to figure out what your power requirements are though. You need real numbers for total working wattage (Volt*Amps=Wattage). Lights, ignition, losses due to resistance, etc... Only then will you know what the strain is on the batterey or how big of a cap (and it's rating) do you need. Or, use a baatterey plus a big cap?


Sorry for the long, unclear reply. Had a glass of wine

[vin63]

Just my experience from Super Class and bracket racing for 20+ years...if you run a 12 volt battery(s) and an MSD ignition, especially a 7AlL2 or higher, I would highly recommend an alternator - these ignitions do not like any slight voltage drop. I tried not running an alternator my first couple of seasons and my car was inconsistent - death in index racing. Going with an alternator cleared all of that up for me (not after spending a lot of money on different torque converters, slicks and carburetors first)...I could've save myself a lot of headaches, frustration and money.

If you still prefer not running an alternator, I would recommend going to a 16 volt battery.

Originally Posted by Super73

...Coming from a somewhat electrical background (I have worked in the semiconductor industyr for 12+ years helping engineers design circuits...

Which company(s)? I also worked in the semiconductor and related industries in communications since the late 80s. I did media, public, and investor relations for Applied Materials, Novellus Systems, Cypress, KLA-Tencor, PMC Sierra, etc.

[Marv D]

Did the same,, tried for 2 years to run on a battery charger and 2 optimas... learned,, a good racing alternator is worth what they want for them.
There is a reason they call them "starting batteries". They are not "run everything off of them" batteries,, STARTING battteries!

this one from slummit is a decent 100amp racing alternator. Made for the high RPMS, high load, deep groove pullley so it's not tossing belts,, one wire, mounting / pulley position works great with a motor plate , and under $200. I've had great luck with them.

If you prefer the nippondenso type,, A little less amps, a little more $, but there really reliable too,,,

Just my 2¢ but be cautious of the 'powermaster' stuff. Old (90's early 2000's) stuff was rock solid,, but everything I've gotten from John in the last 5-6 years has been full of crappy parts and not ,, well...... not very 'durable' and I'll leave it at that.

[hotrod 80]

Disadvantages for me are 1/4 mile track doesn't have power outlets for a charger which means hauling a generator . As voltage lower electronics start to not operate properly . Alternator for me as many amps as possible .

[dbmx66]

looks like ill be keeping it on haha, it was just something ive wondered about and wanted to know the details, thanks guys

[Super73]

I have worked for companies such as Jaco Electronics, Reptron, All American, WPG (World Piece Group) and a direct manufactures rep, I work for TTI right now. So I have sold everything from Samsung Dram/TFT Displays, 10k watt AC/DC power supplies, board level discrete power solutions (Mosfetts, magnetics etc.), Microcontrollers, High bright LED's.... Too much to list.


You can think of a cap like a batterey, it stores energy, but it doesn't hold a charge like a batterey. There is leakdown and there will be voltage loss if not kept charged. I honesty think if someone put a big cap in between the batterey and the electronics using the power it would help act as a buffer and the batteries longevity would be better. Now as far as draining the batterey, you will still see a voltage drop, but the bigger the cap, the less voltage drop you would see, given the same amount of run time. So you would still need to charge between rounds. I think the inconsistant ET's would lessen. So here are the pro's con's..

Pro:
Possibly more power due to not spinning the alternator

Con's even with a cap:
Constant charging between rounds
Inconsistant ET's?
Large caps come with weight and mounting issues